have you flown a twin? counter rotating engines help with p-effect on the rudder and would help eliminate yaw but the deathroll would still occur.deathroll is when the wing panel with the running engise risesand the wing panel with dead engine drops at full power the plane will do an axial roll of close to one per second compared to the one in 5 seconds using airlerons.downthrust should slow the roll rate so you can recover and landgyro coupeled to the rudder will also help correct.you do not want to use airlerons .